Diazo compounds are important carcinogens and carcinolytes. The objectives of the present research are to: (1) study transformations of heterocyclic diazo compounds, N-nitrosoureas, and their derivatives as necessary to allow preparation of materials of improved carcinolytic activity, and (3) provide experimental quantities and/or laboratory methods for various agents so that their antineoplastic properties can be evaluated. The study will include: (1) determination of the thermal and photochemical reactions of 5-(3,3-dimethyl-1-triazeno)imidazole-4-carboxamide (DTIC), 5-3,3-bis(2-chloroethyl)-1-triazeno)-4-carboxamide (DCTIC), 4-diazoimidazoles, and related diazo heterocyclic derivatives, (2) chemical transformation of 3-alkyl-1-(haloalkyl)-1-nitrosoureas to new types of antineoplastic compounds, (3) synthesis of novel diazo compounds, alkenylidenediazo compounds, displaceable diazirines, alkenylidenediazirines, N-nitroso-N-vinylamides, N-vinylazoxy compounds, and heteracyclopropenes, and (4) investigation of the preparation and chemistry of diazothiopyrans, diazodihydropyridines, and diazopyrans and their corresponding carbenes. The information from the present investigation will be used to direct advantageous specific synthesis of products of medical significance and to test the basic postulates of this proposal for cancer chemotherapy.